In a sequential picking system, a number of different articles are separately stacked in dispensers mounted alongside a moving conveyor. Through operation of a computer program, articles are selectively dispensed from the dispensers onto the conveyor, and the articles are then conveyed to a location where they can be packaged for shipment to the customer.
As an example of a sequential picking system, video cassettes, each containing a different videotape, or small cardboard cartons containing pharmaceuticals or drug products, can be stacked in separate dispensers along the conveyor, and individually dispensed onto the conveyor to fill a purchase order.
In the past, dispensers as used in a sequential picking system have included an elongated vertical supporting structure, in which the articles are stacked. The conventional dispenser requires that the articles be top loaded into the dispenser and manual top loading is difficult and time consuming.
In a conventional dispenser, the lowermost article in the stack is normally supported throughout its surface area on a base or support, and a pusher acts to push the lowermost article across the base and onto the moving conveyor. The stroke of the pusher is determined by the size of the article, and in many cases the stroke may be several inches or more. Because of the long stroke, the delivery rate of the dispenser is relatively slow. A further problem arises in that pushing the article across the base may tend to wear off printing or other finish that is applied to the surface of the article.
As the entire accumulated weight of the stack is on the lowermost article in the stack, there is considerable frictional resistance to the displacement of the lowermost article by the pusher, with the result that the other articles in the stack will tend to move with the lowermost article. Thus, it is necessary to incorporate a stripper, which will prevent the second lowermost article, as well as all articles above the second lowermost article, from being displaced as the lowermost article is moved by the pusher.